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Re: An alternative TP hole approach?

2004-10-19 by Dave Mucha

--- In Homebrew_PCBs@yahoogroups.com, "thespeakerguy" 
<thespeakerguy@y...> wrote:
> 
> I was wondering if this may ne a reasonable approach:
> 
> 1 - Drill the blank copper clad board with slightly oversize holes.
> 
> 2 - Squeeege conductive epoxy into the holes. Cure
> 
> 3 - re drill the holes to the correct size
> 
> 4 - electroplate, photo mask, then etch.
> 
> This assumes a CNC based drill with good repeatability. It could 
> work with LPKF and other grinders, as well as home brews


I would think the holes would need to be large.  If the hole were 
thin, it would not stand up to the presures in re-drilling and would 
probably rip out of the hole.  I think I would put a hole next to a 
hole.  The first for epoxy to make a bridge, then one for the part.  
That way, re-drilling is not critical.

Considder what Stefan said many months ago.

Look at your board.  A resistor can be soldered on both sides, thus 
connecting traces, thus eleminating a thru hole for that trace.    
With a cap and diode and transistor, it is quickly found that the 
unconnected traces are so few that the fix of bridging those 
remaining are not a problem.

If you look at your epoxy idea, that could be for those hard to 
connect traces.    My question is the reliability of the epoxy joint 
on conductivity.

Dave

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